The field of wireless communications has many applications including, e.g., cordless telephones, paging, cellular, wireless local loops, and satellite communication systems. A particularly important application is cellular telephone systems (also including Personal Communications Services (PCS) for mobile subscribers.
Wireless communication devices, such as cellular telephones, are widely used as a replacement for conventional telephone systems. Hereinafter the term cellular will be used to refer to any wireless communication device. In addition to functioning as a replacement for a conventional telephone, wireless communication devices offer the advantage of portability, thus enabling the user to establish a wireless communication link between virtually any two locations on Earth.
In addition to conventional voice communication, wireless communication devices also provide features such as voicemail, voice messaging, and automatic callback notification. Callback notification allows a caller to automatically transmit his telephone number to simplify the process of returning a call. For example, the user of a wireless telephone may place a call (the calling party) that is not received by the intended recipient. A message may be left for the intended recipient (the called party) and include a “callback number,” which corresponds to the caller's mobile identification number. The message recipient may readily establish a communication link with the wireless communication device using the callback number.
Other features, such as three-way calling, are also readily implemented using the conventional communication device. The user of the wireless communication device may establish a first communication link by selecting a stored telephone number from a telephone book storage area within the wireless communication device. When the first communication link is established, the user establishes the second communication link by manually entering a second destination telephone number or by selecting a second destination telephone number from the telephone book storage area.
An additional group of features include voicemail services. Typical services provide for the automatic unattended answering of a call after a predetermined number of rings. Traditional voicemail services fall short in some instances. For example, people in public places such as movie theaters, restaurants and meetings often are interrupted by incoming telephone calls. There are occasions when the receiving person desires to answer the call but is unable to immediately do so. What is needed is a mechanism to allow the receiving party to respond to the incoming call with a minimal amount of disruption to public proceedings around him or her.